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Delphi using Environment Variables in your App

Environment Variables can help you extract data that require some in-depth coding to achieve the same result. So here is a simple way to replace lengthy legacy code or create some new code with

function GetEnvironmentVariable(const Name: string): string; found in the System.SysUtils library.

What it is?

The ‘GetEnvironmentVariable’ method is a way to retrieve the value of an environment variable passed as a string (name) for the current process using a standard list of Windows based variables that can be extracted.

How useful is it?

These Environment Variables are a standard across all OS’s and for different processors thereby ensuring that there is no requirements for ‘IFDEFs’.

I found it useful to extract :-

• certain directories such as ‘Appdata’ that calls the Roaming directory.
• to determine / show who has logged onto the Windows machine.
• extract the CMD.exe directory using ‘Comspec’.
• Obtaining the OS Processor info.
• obtaining the ‘Tmp / Temp’ drive for processing.

Check out the simple App that calls each Environment Variable via a combobox that shows the result real time on your Windows machine. Perhaps there are a few other options that you could find useful.

Here is the list of the Standard Environment Variables.

Environment variable name	Environment value
ALLUSERSPROFILE	Generic user profile.
APPDATA	Path of the application data folder.
CLIENTNAME	Name of Client machine.
COMMONPROGRAMFILES	Path of common program files folder.
COMPUTERNAME	Name of Computer code is running on.
COMSPEC	Path of the cmd.exe program.
HOMEDRIVE	Current home drive designation, such as 'C:'
HOMEPATH	Path to current location for document storage.
LOGONSERVER	Specifies a domain controller for user logon authentication.
NUMBER_OF_PROCESSORS	Number of processors on current machine.
OS	Base name of the Operating System.
PATH	The current program path.
PATHEXT	Extension types of executable files.
PROCESSOR_ARCHITECTURE	Type of CPU architecture. For example, X86 for Intel Pentium processors.
PROCESSOR_IDENTIFIER	ID number of current machine.
PROCESSOR_LEVEL	More detailed description of the CPU architecture.
PROCESSOR_REVISION	Processor revision level.
PROGRAMFILES	Path of the program files folder.
SESSIONNAME	Name of the current OS session.
SYSTEMDRIVE	Drive the OS operates from.
SYSTEMROOT	Sets the system directory.
TEMP	Path of the temporary files folder.
TMP	Directory to store temporary files to.
USERDOMAIN	Specifies the domain of the current machine.
USERNAME	Name of the current user.
USERPROFILE	Path of the folder holding the current user's information.
WINDIR	Path of the Windows folder.

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Happy Coding